Organic light emitting display device with substantially polygonal sub-pixels

ABSTRACT

An organic light emitting display device includes a plurality of sub-pixels arranged in a substantially hexagonally-shaped structure, each of the sub-pixels including a corresponding one of a plurality of organic light emitting devices, wherein the plurality of sub-pixels includes a plurality of first sub-pixels for emitting light of a first color, a plurality of second sub-pixels for emitting light of a second color, and a plurality of third sub-pixels for emitting light of a third color, and wherein centers of adjacent ones of the first, second, and third sub-pixels form a triangle having one of three sides that is shorter than the other two of the sides.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/056,926, filed Oct. 17, 2013, which is a continuation of U.S. patentapplication Ser. No. 13/448,947, filed Apr. 17, 2012, issued as U.S.Pat. No. 6,598,784, which claims priority to and the benefit of KoreanPatent Application No. 10-2011-0065141, filed on Jun. 30, 2011, in theKorean Intellectual Property Office, the disclosures of each of whichare incorporated herein in their entirety by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to an organic light emittingdisplay device.

2. Description of Related Art

Organic light emitting display devices are self-emissive displays thatemit light by electrically exciting organic compounds, and are beingconsidered as next generation display devices that may address problemsof liquid crystal display devices, as organic light emitting displaydevices may operate with low voltage, may have a thin profile, and havewide viewing angles and fast response speeds. Therefore, demands fororganic light emitting display devices with high resolution areincreasing.

A light emission layer in each of sub-pixels that emit light ispatterned by colors for realizing full-white color, and to do this, adeposition process using a fine metal mask is performed. However, thereis a limitation in finely patterning each of the sub-pixels according tothe deposition process using a fine metal mask.

Accordingly, an aperture ratio, which is a ratio of an actual lightemitting area to an entire display screen of the organic light emittingdisplay device, is reduced as the resolution of the organiclight-emitting display device increases. The reduction of the apertureratio means that a light emitting area in each of the sub-pixels isreduced, and accordingly, the lifespan of the organic light emittingdisplay device may be degraded.

SUMMARY

Embodiments of the present invention provide an organic light emittingdisplay device with an increased lifespan by increasing an apertureratio.

Embodiments of the present invention also provide an organic lightemitting display device capable of reducing or preventing image qualitydegradation.

According to an aspect of embodiments of the present invention, there isprovided an organic light emitting display device including a pluralityof sub-pixels arranged in a substantially hexagonally-shaped structure,each of the sub-pixels including a corresponding one of a plurality oforganic light emitting devices, wherein the plurality of sub-pixelsincludes a plurality of first sub-pixels for emitting light of a firstcolor, a plurality of second sub-pixels for emitting light of a secondcolor, and a plurality of third sub-pixels for emitting light of a thirdcolor, and wherein centers of adjacent ones of the first, second, andthird sub-pixels form a triangle having one of three sides that isshorter than the other two of the sides.

The three sides of the triangle may have different lengths.

The first color may be green, the second color may be blue, and thethird color may be red.

According to another aspect of embodiments of the present invention,there is provided an organic light emitting display device including aplurality of sub-pixels arranged in a substantially hexagonally-shapedstructure, each of the sub-pixels including a corresponding one of aplurality of organic light emitting devices, wherein the plurality ofsub-pixels includes a plurality of first sub-pixels for emitting lightof a first color, a plurality of second sub-pixels for emitting light ofa second color, and a plurality of third sub-pixels for emitting lightof a third color, wherein sub-pixels of different colors from among theplurality of sub-pixels are adjacent in a first direction and areadjacent in a second direction that is perpendicular to the firstdirection, and wherein a first center line through centers of the firstsub-pixels in the second direction is separated from a second centerline through centers of the second sub-pixels in the second direction,the second sub-pixels being adjacent to corresponding ones of the firstsub-pixels in the second direction.

A third center line through centers of the third sub-pixels in thesecond direction may coincide with the second center line, the thirdsub-pixels being adjacent to corresponding ones of the first sub-pixelsin the second direction.

A third center line through centers of the third sub-pixels in thesecond direction may coincide with the first center line, the thirdsub-pixels being adjacent to corresponding ones of the first sub-pixelsin the second direction.

A third center line through centers of the third sub-pixels in thesecond direction may be separated from the second center line, the thirdsub-pixels being adjacent to corresponding ones of the first sub-pixelsin the second direction.

A distance between the centers of two of the first sub-pixels that arenearest in the first direction may be shorter than a distance betweenthe centers of two of the second sub-pixels that are nearest in thefirst direction.

A distance between the centers of two of the first sub-pixels that arenearest in the first direction may be shorter than a distance betweenthe centers of two of the third sub-pixels that are nearest in the firstdirection.

A distance between the centers of two of the third sub-pixels that arenearest in the first direction may be shorter than a distance betweenthe centers of two of the second sub-pixels that are nearest in thefirst direction.

The first color may be green, the second color may be blue, and thethird color may be red.

According to another aspect of embodiments of the present invention,there is provided an organic light emitting display device including aplurality of sub-pixels arranged in a substantially hexagonally-shapedstructure, each of the sub-pixels including a corresponding one of aplurality of organic light emitting devices, wherein the plurality ofsub-pixels includes a plurality of first sub-pixels for emitting lightof a first color, a plurality of second sub-pixels for emitting light ofa second color that is different from the first color, and a pluralityof third sub-pixels for emitting light of a third color that isdifferent from the first and second colors, wherein sub-pixels ofdifferent colors from among the plurality of sub-pixels are adjacentalong a first axis and are adjacent along a second axis that isperpendicular to the first axis, and wherein a width of each of thefirst sub-pixels along the first axis is narrower than a width of eachof the second sub-pixels along the first axis.

The width of one of the first sub-pixels along the first axis may benarrower than a width of the one of the first sub-pixels along thesecond axis.

Centers of the first sub-pixels in a column arranged along the secondaxis may be offset along the first axis from centers of the secondsub-pixels arranged in the column.

The centers of the first sub-pixels in odd number columns and thecenters of the first sub-pixels in even number columns may be shifted inopposite directions along the first axis.

A width of each of the third sub-pixels along the first axis may benarrower than a width of each of the second sub-pixels along the firstaxis.

The width of one of the third sub-pixels along the first axis may benarrower than a width of the one of the third sub-pixels along thesecond axis.

Centers of the third sub-pixels in a column arranged along the secondaxis may be offset along the first axis from centers of the secondsub-pixels arranged in the column.

The centers of the third sub-pixels in odd number columns and thecenters of the third sub-pixels in even number columns may be shiftedalong the first axis in opposite directions.

A width of each of the second sub-pixels along the first axis may benarrower than a width of each of the second sub-pixels along the secondaxis.

The first color may be green, the second color may be blue, and thethird color may be red.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and aspects of embodiments of the presentinvention will become more apparent by describing in detail exemplaryembodiments thereof with reference to the attached drawings in which:

FIG. 1 is a plan view of sub-pixels in an organic light emitting displaydevice according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of one of a plurality of sub-pixels ofthe embodiment shown in FIG. 1;

FIG. 3 is a plan view of first sub-pixels in one column from among thesub-pixels of the embodiment shown in FIG. 1;

FIG. 4 is a plan view of second sub-pixels in one column from among thesub-pixels of the embodiment shown in FIG. 1;

FIG. 5 is a plan view of sub-pixels in an organic light emitting displaydevice according to another embodiment of the present invention; and

FIG. 6 is a plan view of sub-pixels in an organic light emitting displaydevice according to yet another embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, embodiments of an organic light emitting display deviceaccording to the present invention will be described with reference toaccompanying drawings.

FIG. 1 is a plan view of sub-pixels in an organic light emitting displaydevice according to an embodiment of the present invention.

Referring to FIG. 1, the organic light emitting display device accordingto the present embodiment includes sub-pixels, with each of thesub-pixels being substantially hexagon-shaped (e.g., six sided) andarranged in a substantially hexagonal structure.

Each of the sub-pixels includes a pixel circuit including an organiclight emitting device and a thin film transistor.

FIG. 2 is a cross-sectional view of one of the sub-pixels of theembodiment shown in FIG. 1.

As shown in FIG. 2, a thin film transistor T is formed on a substrate40, and an organic light emitting device 50 that is electrically coupledto the thin film transistor T is located on the substrate 40.

A buffer layer 41 is formed on the substrate 40, and the thin filmtransistor T is located on the buffer layer 41.

The buffer layer 41 reduces or prevents impurity elements frompenetrating into the substrate 40, and planarizes the surface of thesubstrate 40. The buffer layer 41 may be formed of various materials.For example, the buffer layer 41 may be formed of an inorganic material,such as silicon oxide, silicon nitride, silicon oxinitride, aluminumoxide, aluminum nitride, titanium oxide, or titanium nitride, may beformed of an organic material, such as polyimide, polyester, or acryl,or may be formed of a stacked structure thereof. However, the bufferlayer 41 is not an essential element, that is, the buffer layer 41 isnot necessary to practice the embodiments of the present invention.

An active layer 42, which is formed of a semiconductor material, ispatterned on the buffer layer 41. The active layer 42 may be formed ofpolycrystalline silicon;

however, the present embodiment is not limited thereto, that is, theactive layer 42 may be formed of other materials, such as an oxidesemiconductor. For example, the active layer 42 may be a G-I—Z—O layer[e.g., a (In₂O₃)a(Ga₂O₃)b(ZnO)c layer, wherein a, b, and c arerespectively real numbers respectively satisfying conditions of a≧0,b≧0, and c>0].

A gate insulating layer 43 is formed on the buffer layer 41 so as tocover the active layer 42, and a gate electrode 44 is formed on the gateinsulating layer 43.

An interlayer dielectric 45 is formed on the gate insulating layer 43 soas to cover the gate electrode 44. A source electrode 46 and a drainelectrode 47 are formed on the interlayer dielectric 45 to contact theactive layer 42 through respective contact holes.

According to the present embodiment, at least one thin film transistor Tis located in each of the sub-pixels. In addition, FIG. 2 shows one thinfilm transistor T; however, the present invention is not limitedthereto. That is, a plurality of thin film transistors T may be locatedin each of the sub-pixels to configure a pixel circuit unit, and thepixel circuit unit may further include a capacitor.

The thin film transistor T is covered by a first insulating layer 48.The first insulating layer 48 is a layer-shaped structure including atleast one layer formed on the interlayer dielectric 45, and may beformed of an organic material and/or an inorganic material. The organicmaterial may be, for example, a polymer material such as acryl,polyimide, or polyester, and the inorganic material may be, for example,silicon oxide, silicon nitride, silicon oxinitride, aluminum oxide,aluminum nitride, titanium oxide, or titanium nitride.

A first electrode 51 is formed on the first insulating layer 48. Thefirst electrode 51 is coupled to the drain electrode 47 via a via-holeformed in the first insulating layer 48.

In addition, a second insulating layer 54 is formed on the firstinsulating layer 48, and the second insulating layer 54 covers an edgeof the first electrode 51. The second insulating layer 54 includes anopening 55 exposing a part of the first electrode 51. The secondinsulating layer 54 may be formed of an organic material such as acryl,polyimide, or polyester; however, the present invention is not limitedthereto, that is, the second insulating layer 54 may be formed of aninorganic material or an organic/inorganic compound.

An organic emission layer 53 is formed on the first electrode 51 and thesecond insulating layer 54 so as to cover the part of the firstelectrode 51 that is exposed by the opening 55, and a second electrode52 is formed on the organic emission layer 53 and the second insulatinglayer 54 so as to cover the organic emission layer 53.

The first electrode 51 is patterned independently on each of thesub-pixels, and the second electrode 52 is formed as a common electrode(e.g., an electrode that covers all the sub-pixels). The opening 55 ofthe second insulating layer 54 is formed in each of the sub-pixels, andan area of the opening 55 is substantially the same as an area of thelight emitting region in the sub-pixel. In the sub-pixel having thehexagonal structure of the embodiment shown in FIG. 1, the opening 55 isformed to have a substantially hexagonal plane shape. The opening 55 andthe first electrode 51 do not need to have the same plane shapes, andthe first electrode 51 may be formed to have another shape, for example,a triangular or other polygonal shape.

The first electrode 51, the second electrode 52, and the organicemission layer 53 form the organic light emitting device 50.

The first electrode 51 and the second electrode 52 may have polaritiesthat are opposite to each other, that is, may be formed respectively asan anode and a cathode. Alternatively, the first electrode 51 may be acathode and the second electrode 52 may be an anode.

In any case, the electrode functioning as the anode includes aconductive material having a work function of a high absolute value, andthe electrode functioning as the cathode includes a conductive materialhaving a work function of a low absolute value. The conductive materialhaving a high work function may be a transparent conductive oxidematerial such as, for example, indium tin oxide (ITO), In₂O₃, ZnO, orindium zinc oxide (IZO), or a noble metal such as Au. The conductivematerial having a low work function may be, for example, Ag, Al, Mg, Li,Ca, LiF/Ca, or LiF/Al.

In a top emission type display device in which images are displayedtoward a direction away from the substrate 40, the first electrode 51includes a light reflective material, and the second electrode 52 is alight transmission type electrode.

To do this, when the first electrode 51 functions as the anode, areflective body is formed of, for example, Ag, Mg, Al, Pt, Pd, Au, Ni,Nd, Ir, Cr, or a compound thereof, and then, ITO, IZO, ZnO, or In₂O₃having the high work function, for example, is deposited on thereflective body. In addition, when the first electrode 51 functions asthe cathode, the first electrode 51 is formed of, for example, Ag, Al,Mg, Li, Ca, LiF/Ca, or LiF/Al having low work function and is capable ofreflecting light.

When the second electrode 52 functions as the cathode, the secondelectrode 52 may be formed to be thin for performing as a transflectivelayer by using a metal material such as, for example, Li, Ca, LiF/Ca,LiF/Al, Al, Mg, or Ag having low work function. The transparentconductive material such as, for example, ITO, IZO, ZnO, or In₂O₃ may bedeposited on the metal transflective layer to address high resistancecaused due to the thinness of the transflective layer. When the secondelectrode 52 functions as the anode, the second electrode 52 may beformed of, for example, ITO, IZO, ZnO, or In₂O₃.

The first and second electrodes 51 and 52 may be formed of various othermaterials that are known to those of ordinary skill in the art.

The first and second electrodes 51 and 52 apply voltages of oppositepolarities to the organic emission layer 53 between the first and secondelectrodes 51 and 52 to make the organic emission layer 53 emit light.

The organic emission layer 53 may be formed of a low-molecular weightorganic material or a high-molecular weight organic material. If alow-molecular weight organic material is used, then the organic emissionlayer 63 may have a single or multi-layer structure including at leastone selected from the group consisting of a hole injection layer (HIL),a hole transport layer (HTL), an emission layer (EML), an electrontransport layer (ETL), and an electron injection layer (EIL). Examplesof available organic materials may include, for example, copperphthalocyanine (CuPc), N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine(NPB), tris-8-hydroxyquinoline aluminum (Alq3), and the like. Such alow-molecular weight organic material may be deposited by vacuumdeposition.

If a high-molecular weight organic material is used, the organicemission layer 53 may have a structure including the HTL and EML. Here,the HTL may be formed of, for example, poly(3,4-ethylenedioxythiophene)(PEDOT), and the EML may be formed of, for example, a polymer organicmaterial based on PolyPhenylene Vinylene (PPV) and Polyfluorene in ascreen printing method or an inkjet printing method.

The organic emission layer 53 is not limited to the above examples, andother examples may be applied.

FIG. 1 is a plan view of the sub-pixels of the above cross-sectionalstructures.

The organic light emitting display device of the present embodimentincludes a plurality of sub-pixels as shown in FIG. 1.

The plurality of sub-pixels include a plurality of first sub-pixels 1for emitting light of a first color, a plurality of second sub-pixels 2for emitting light of a second color that is different from the firstcolor, and a plurality of third sub-pixels 3 for emitting light of athird color that is different from the first and second colors.

The first through third colors may mix to emit white light, and in thepresent embodiment, the first through third colors may be respectivelygreen, blue, and red. However, the present invention is not limitedthereto, that is, the first through third colors may be, for example,yellow, cyan, and magenta, respectively.

In the present embodiment, the first color is a color having high colorperception. When the sub-pixels emit the green, blue, and red lights,the green color is the most recognizable color to humans, and thus, thefirst color is green.

When the sub-pixels include green, blue, and red sub-pixels, the organiclight emitting material forming the blue sub-pixels, that is, the secondcolor, has the shortest lifespan from among the three colors.

Each of the sub-pixels is hexagonally shaped, and the sub-pixels arearranged with a substantially hexagonal structure. The hexagonalstructure corresponds to the plane shape of the opening 55 formed in thesecond insulating layer 54 shown in FIG. 2.

Therefore, each of the first sub-pixels 1 has a first opening 551 formedas a hexagon, each of the second sub-pixels 2 has a second opening 552formed as the hexagon, and each of the third sub-pixels 3 has a thirdopening 553 formed as a hexagon. Therefore, the light emission region ofthe first sub-pixel 1 corresponds to the first opening 551, the lightemission region of the second sub-pixel 2 corresponds to the secondopening 552, and the light emission region of the third sub-pixel 3corresponds to the third opening 553.

With respect to embodiments of the present invention, descriptions aboutthe first sub-pixel 1 through the third sub-pixel 3 are for the lightemission regions of the sub-pixels 1 through 3, and actually, theregions corresponding to the first through third openings 551 through553.

In the embodiment of the present invention shown in FIG. 1, thesub-pixels are arranged in a substantially hexagonal shape, and thus,the sub-pixels are arranged in zigzags when viewed along a firstdirection (e.g., along the x-axis, or in the x direction depicted inFIG. 1) that is a transverse direction, while the sub-pixels arearranged linearly when viewed along a second direction (e.g., along they-axis, or in the y direction depicted in FIG. 1) that is a longitudinaldirection that is perpendicular to the first direction. In addition, thefirst sub-pixel 1, the second sub-pixel 2, and the third sub-pixel 3 aresequentially arranged in a straight line along the second direction (ydirection), and other ones of the first through third sub-pixels 1through 3 are sequentially arranged in a straight line along the seconddirection (y direction) that is adjacent to the above line in the firstdirection (x direction). Here, around a given sub-pixel, only sub-pixelsof different colors are arranged, and thus, centers of the firstsub-pixel 1, the second sub-pixel 2, and the third sub-pixel 3 that areadjacent to each other form a triangle.

According to the sub-pixels arranged in a hexagonal shape, the apertureratio is greater than a structure in which the sub-pixels are arrangedin a rectangular shape. Therefore, according to the present embodiment,an aperture ratio that is higher than that of an organic light emittingdisplay device including sub-pixels arranged in a rectangular shape maybe obtained.

In the above arrangement of the sub-pixels, the sub-pixels of one colorare arranged at every other pixel along the first direction (xdirection), and at every third sub-pixel along the second direction (ydirection). Therefore, a user recognizes that one color is arranged inzigzag along the second direction (y direction) that is the longitudinaldirection.

According to the embodiment illustrated in FIG. 1, a width of the firstsub-pixel 1 is narrower than those of the second sub-pixel 2 and thethird sub-pixel 3 in the first direction (x direction). Therefore, thewidth of the first sub-pixel 1 in the first direction (x direction) isnarrower than the width of the first sub-pixel 1 in the second direction(y direction).

Here, centers of the first sub-pixels 1 arranged in the second direction(y direction) are shifted to a side in the first direction (x direction)with respect to a second center line through centers of the secondsub-pixels. A first center line that couples the centers of the firstsub-pixels 1 arranged in the second direction (y direction) (e.g., avertical line that passes through centers of first sub-pixels 1) isseparated from the second center line that couples the centers of thesecond sub-pixels 2 arranged in the second direction (y direction)(e.g., a vertical line that passes through centers of second sub-pixels2), the second sub-pixels 2 being adjacent to the first sub-pixels 1 inthe second direction (y direction) (e.g., the first and secondsub-pixels 1 and 2 being in a same column of pixels).

That is, a column of the first sub-pixels 1 arranged in the seconddirection (y direction) and another column of the first sub-pixels 1adjacent to the above column in the first direction (x direction) areshifted in opposite directions (e.g., opposite directions of the xdirection). Therefore, as shown in FIG. 1, the first sub-pixels 1 in thefirst column from the left and the first sub-pixels 1 in the secondcolumn from the left are shifted to face each other. That is, as shownin FIG. 1, the first sub-pixels 1 in odd number columns are shifted tothe right, and the first sub-pixels 1 in even number columns are shiftedto the left.

Centers of adjacent ones of the first through third sub-pixels 1 through3 form a triangle. Here, one side of the triangle is shorter than theother sides of the triangle. According to the embodiment shown in FIG.1, three sides of the triangle have different lengths.

Referring to FIGS. 3 and 4, according to the above-described structure,a horizontal distance d1 between two adjacent first sub-pixels 1 isshorter than a horizontal distance d2 between two adjacent secondsub-pixels 2. Here, the horizontal distances d1 and d2 are distances inthe first direction (x direction).

As described above, the first sub-pixels 1 are the sub-pixels emittingthe green light and have high color perception to humans. Therefore,when the horizontal distance d1 between the centers of the two adjacentfirst sub-pixels 1 is reduced, a width of the zigzag pattern of thefirst sub-pixels 1 arranged in the second direction (y direction) isnarrower than that of the second sub-pixels 2 shown in FIG. 4, and thus,the zigzag pattern of the first sub-pixels 1 is more nearly straight.That is, the green sub-pixels that largely affect perception quality arearranged nearly in a straight line, and thus, degradation of imagequality may be reduced or prevented.

The image quality may be improved without reducing the distances betweenopenings formed in a second insulating layer in a conventional sub-pixelarrangement as shown in FIG. 1, and thus, processing margin may beensured.

The arrangement structure of the first sub-pixels 1 may be formed bychanging the sizes and locations of the first openings 551 formed in thesecond insulating layer 54 without changing a size of the firstelectrode in each of the sub-pixels, and without changing a structure ofthe pixel circuit unit.

Therefore, all fabrication processes of the organic light emittingdisplay device may be performed without being changed.

FIG. 5 shows sub-pixels according to another embodiment of the presentinvention, in which third sub-pixels 3′ are modified in a manner similarto the first sub-pixels 1 described above.

That is, a width of the third sub-pixel 3′ is reduced to be narrowerthan a width of the second sub-pixel 2 in the first direction (xdirection). Therefore, the width of the third sub-pixel 3′ in the firstdirection (x direction) is narrower than the width of the thirdsub-pixel 3′ in the second direction (y direction).

Here, centers of the third sub-pixels 3′ arranged in the seconddirection are shifted to a side in the first direction (x direction).The first center line coupling the centers of the first sub-pixels 1along the second direction (y direction), and a third center linecoupling centers of the third sub-pixels 3′ along the second direction(y direction), the third sub-pixels 3′ being adjacent to the firstsub-pixels 1 along the second direction (y direction), coincide witheach other. In addition, the first center line and the third center lineare separated from the second center line coupling the centers of thesecond sub-pixels 2 along the second direction (y direction), the secondsub-pixels 2 being adjacent to the first sub-pixels 1 along the seconddirection (y direction).

That is, a column of the third sub-pixels 3′ arranged in the seconddirection (y direction) and another column of the third sub-pixels 3′that is adjacent in the first direction (x direction) to the abovecolumn are shifted in opposite directions (e.g.,. opposite directionsalong the x-axis). Therefore, the third sub-pixels 3′ in the first andsecond columns from the left in FIG. 5 are shifted to face each other.That is, as shown in FIG. 5, the third sub-pixels 3′ in odd numbercolumns are shifted to the right, and the third sub-pixels 3′ in evennumber columns are shifted to the left.

Here, centers of the first through third sub-pixels 1, 2, and 3′ thatare adjacent to each other form a triangle having three sides ofdifferent lengths.

In addition, a horizontal distance between centers of two adjacent thirdsub-pixels 3′ is shorter than a horizontal distance between centers oftwo adjacent second sub-pixels 2.

In FIG. 5, sizes of the third sub-pixels 3′ are reduced in the samepattern as the first sub-pixels 1; however, the present invention is notlimited thereto. That is, the sizes and locations of the thirdsub-pixels 3′ may be changed regardless of the pattern of the firstsub-pixels 1, and the first center line and the third center line neednot coincide with each other.

According to the present embodiment, the third sub-pixels 3′, as well asthe first sub-pixels 1, are arranged in nearly straight lines in thesecond direction (y direction), and thus, the image quality may befurther improved. In addition, disadvantages of the hexagonal sub-pixelstructure may be avoided, while still maintaining the advantages of thehexagonal sub-pixel structure.

FIG. 6 shows sub-pixels according to another embodiment of the presentinvention, in which structures of second sub-pixels 2′ are changed inaddition to the sub-pixels 1 and 3′ of the embodiment of FIG. 5.

In the case of the second sub-pixels 2′ emitting the blue light, thebrightness of the light emitted from the second sub-pixels 2′ may bedegraded due to the short lifespan of the blue emitting material.Therefore, as shown in FIG. 6, if the sizes of the second sub-pixels 2′are increased by an amount equal to the amount that the reduced sizes ofthe first sub-pixels 1 and the third sub-pixels 3′ are decreased, theblue emission area increases, and thus, the lifespan degradation of theblue emitting material and the brightness degradation may be reduced.

That is, as shown in FIG. 6, a width in the first direction (xdirection) of the second sub-pixel 2′ of the present embodiment isincreased to be wider than the width of the second sub-pixel 2 in thefirst direction (x direction) of the embodiments shown in FIGS. 1 and 5.Therefore, the width of the second sub-pixel 2′ in the first direction(x direction) may be greater than a width of the second sub-pixel 2′ inthe second direction (y direction).

Here, the first center line coupling the centers of the first sub-pixels1 along the second direction (y direction), and the third center linecoupling the centers of the third sub-pixels 3′ in the second direction(y direction), coincide with each other, the third sub-pixels 3′ beingadjacent to the first sub-pixels 1′ along the second direction (ydirection) (e.g., the third sub-pixels 3′ being in the same column asthe first sub-pixels 1). In addition, the first center line and thethird center line are separated from the second center line coupling thecenters of the second sub-pixels 2′ in the second direction (ydirection), the second sub-pixels 2′ being adjacent to the firstsub-pixels 1 along the second direction (y direction) (e.g., the secondsub-pixels 2′ being in the same column as the first sub-pixels 1).

Since the second sub-pixel 2′ emitting the blue light least affects thedisplay image quality even when the sizes of the second sub-pixels 2′are increased, the image quality of the entire display device is notgreatly reduced.

In addition, since the sizes of the second sub-pixels 2′ are increasedas much as the reduced sizes of the first sub-pixels 1 and the thirdsub-pixels 3′ are decreased, the distances between the first openings551 through the third openings 553′ formed in the second insulatinglayer 54 are not decreased, and accordingly, a processing margin may bemaintained to be the same as a conventional organic light emittingdisplay device.

According to the present embodiment, the first and the third sub-pixelsare arranged in patterns that are nearly in straight lines in the seconddirection, an image quality may be improved, and the lifespan of thesecond sub-pixels may be increased.

The above-described pixel structure of the present embodiment is notlimited to the sub-pixels having hexagonal plane structures as shown inFIGS. 1 and 3 through 6, and may be applied to the sub-pixels havingcircular, oval, square, or other polygonal plane shapes. However, in theabove cases, the sub-pixels of different colors are adjacent to eachother in the first direction and the second direction.

According to embodiments of the present invention, the following effectsmay be obtained:

Since sub-pixels having substantially hexagonal structures are formed,the aperture ratio may be improved, and the lifespan of an organic lightemitting display device is also increased;

The first sub-pixels emitting the green light are arranged in a patternthat is nearly in a straight line in the longitudinal direction, thusreducing or preventing degradation of image quality;

In addition, distances between openings formed in a second insulatinglayer are not reduced, and thus, a processing margin may be ensured;

In addition, the third sub-pixels, as well as the first sub-pixels, arearranged in the pattern that is nearly in a straight line in thelongitudinal direction, and thus, image quality may be further improved,and the disadvantages of the hexagonal sub-pixel structure may beavoided while improving the advantages of the hexagonal sub-pixelstructure;

By increasing the sizes of the second sub-pixels emitting the bluelight, the lifespan of the second sub-pixels emitting the blue light maybe increased, and brightness degradation may be reduced or prevented;

In addition, the sizes of the second sub-pixels are increased as much asthe sizes of the first sub-pixels and the third sub-pixels aredecreased, and thus, the distances between the first through secondopenings formed in the second insulating layer, and accordingly, aprocessing margin, may remain unchanged.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims, andequivalents thereof.

What is claimed is:
 1. An organic light emitting display devicecomprising: a plurality of sub-pixels, each of the sub-pixels comprisinga corresponding one of a plurality of organic light emitting devices,wherein the plurality of sub-pixels comprises: a plurality of firstsub-pixels for emitting light of a first color; a plurality of secondsub-pixels for emitting light of a second color; and a plurality ofthird sub-pixels for emitting light of a third color, and whereincenters of adjacent ones of the first, second, and third sub-pixelshaving no intervening sub-pixels therebetween form a triangle having oneof three sides that has different length from lengths of the other twoof the sides, wherein the plurality of sub-pixels are arranged in firstand second columns along a first direction, each of the columnsextending in a second direction substantially perpendicular to the firstdirection, each of the first columns comprising at least one of thefirst sub-pixels, each of the second columns comprising at least one ofthe second sub-pixels and at least one of the third sub-pixels, andwherein the centers of the first sub-pixels are arranged along the firstdirection with no intervening portion of the second sub-pixels or thethird sub-pixels therebetween.
 2. The organic light emitting displaydevice of claim 1, wherein the first color is green, the second color isblue, and the third color is red.
 3. The organic light emitting displaydevice of claim 1, wherein a width of at least one of the first subpixels along the first direction is narrower than a width of at leastone of the second sub pixels along the first direction.
 4. The organiclight emitting display device of claim 1, wherein a width of at leastone of the third sub pixels along the first direction is narrower than awidth of at least one of the first sub pixels along the first direction.5. An organic light emitting display device comprising: a plurality ofsub-pixels, each of the sub-pixels comprising a corresponding one of aplurality of organic light emitting devices, wherein the plurality ofsub-pixels comprises: a plurality of first sub-pixels for emitting lightof a first color; a plurality of second sub-pixels for emitting light ofa second color; and a plurality of third sub-pixels for emitting lightof a third color, wherein the first, second and third sub-pixels arearranged in a column direction, and wherein a first center line in thecolumn direction through centers of aligned ones of the first sub-pixelsis separated from a second center line in the column direction throughcenters of aligned ones of the second sub-pixels, the aligned ones ofthe second sub-pixels being adjacent corresponding ones of the alignedones of the first sub-pixels in the column direction.
 6. The organiclight emitting display device of claim 5, wherein a third center line inthe column direction through centers of aligned ones of the thirdsub-pixels is separated from the first center line, the aligned ones ofthe third sub-pixels being adjacent corresponding ones of the alignedones of the first sub-pixels in the column direction.
 7. The organiclight emitting display device of claim 6, wherein a distance between thefirst center line and the third center line is shorter than a distancebetween the first center line and the second center line.
 8. The organiclight emitting display device of claim 7, wherein the first color isgreen, the second color is blue, and the third color is red.